The Cellbots project - using an Android smartphone as the brain for a relatively cheap robot - has had an upgrade, with a dashing new neon green chassis and, more impressively, voice control. The system takes advantage of Android's native voice recognition engine, and allows the Cellbot robot to be controlled via speech commands.
In fact, thanks to Google's recognition engine, the team only required a single line of code - (droid.recognizeSpeech() if you're interested - to take advantage of the functionality. Just as with voice-controlled searches, the Android phone listens out for speech and asks you to repeat if it can't understand the directions.
If you want to try it out yourself, there's more on the project as a whole here together with downloadable code including the voice control support. Anybody planning on building a tiny Android robot of their own?